The Effects of Environmental Contaminations on the Dust Induced Corrosion of Electrical Components in Printed Circuit Boards

The corrosion behavior on the standardized test printed circuit boards was evaluated with the effect of chloride- and sulfate-containing dusts, native Southwest Asia dust, temperature and humidity.
Under IPC-TM-650 test (85°C and 85% RH), most test boards easily failed, whereas the light 5 wt. % chloride dusted boards with and without corrosion preventive compound (CPC) coatings have lower surface insulation resistance (SIR) values than the reference or cleaned boards. The amount of dust present on the test circuit boards significantly affects the amount of water soluble anions available for leaching onto the test boards. The anion concentration detected on the test board depends on the ion concentration of the dust, the amount and type of dust, as well as the sampling location. When the dust contaminated test boards were exposed to 85 ºC / 85% RH conditions, all of the test patterns failed the SIR measurement. Heavy dusting of the test patterns including all types of dusts caused failure immediately. In addition, chemical dosing of Yuma dust resulted in soil chemistry similar to that found in Iraqi soils, and contamination of test circuit boards with “synthetic” Iraqi dust in both light and heavy loads was possible.